Modeling solar energetic particle by a relativistic kappa-type distribution

A recently developed relativistic kappa-type (KT) is adopted to model the observed spectra of solar energetic protons. The KT distribution is found to fit well with the observed data in the energies of similar to 1-100 MeV and 100-1000 MeV, suggesting that the solar energetic proton flux follows the power law at both the lower energies and the relativistic energies, and the KT distribution may present a further physical insight into those space plasmas where energetic particles exist.